Chapter 101: Steelmaking

Although the transmigrators’ modern fishing vessels had an absolute advantage in reconnaissance capabilities, protection, speed, and maneuverability, their firepower was very weak. If it had been thirty pirate ships this time instead of three, the lone Yu-1 would probably have had a hard time. And the several pirate lords on the seas of Fujian and Guangdong each had the strength of at least three or four hundred ships. In the entire Bopu Harbor, the transmigrators’ range of activities and various facilities had far exceeded the scope of the Bopu camp. More than two hundred transmigrators and commune members were scattered over an extremely vast space, almost completely undefended.

In summary: not only did the navy need to be upgraded, but for the sake of precaution, the port defense work of Bopu Harbor also had to be put on the agenda. The staff’s suggestions included: building forts; mass-producing cannons of a level not lower than that of 1800; producing and stockpiling ammunition; and establishing a coastal guard fleet—this fleet would mainly consist of motorized sailing boats to save the overhaul life of the fishing vessels. The transmigrators would not have the ability to overhaul this type of ship for 5-10 years. They couldn’t even do simple maintenance like applying bottom paint, not because they lacked the materials, but because they couldn’t achieve the anti-rust and toxic effects of modern bottom paint.

The task of building cannons was assigned to the mechanical group of the industrial department. For the machine enthusiasts, this was like a shot of adrenaline. For many days, they had been feeling wronged and frustrated making small hardware parts, and even the mechanical crossbows were all-wood structures. Now they could finally make cannons, and everyone was full of energy. In the workshop of the machinery factory, artillery enthusiasts of all kinds came and went, proposing various plans. The basic styles were mainly concentrated on three types of artillery: the 12-pounder mountain howitzer; the light, flexible, and versatile 92mm infantry gun; and the all-conquering mortar. Each person also added different functions and improvements to these cannons according to their own preferences.

Building cannons required a large amount of steel. The Dengyingzhou had already transported two batches of pig iron ingots and a small amount of wrought iron from Guangzhou, totaling 50 tons. It also brought 20 tons of urgently needed coal, which could roughly meet the initial demand for large-scale steelmaking.

The converter steelmaking method used by the transmigrators, in the 21st century, small converter steelmaking was a backward industry explicitly eliminated by the state, but here it was a truly advanced industry. This industry was located in the Bopu port area.

The choice of Bopu was because the Lingao iron and steel complex was an enterprise that needed to import all its raw materials. Large quantities of coal and iron ore brought by ships could be used nearby. The current steelmaking workshop was just a large brick-pillared shed. On the hardened floor were lined up 4 small converters and 1 cupola furnace.

The head of the metallurgical department, Ji Wusheng, had been a steelworker in the past. Although he had never done small converter steelmaking himself, he understood the principle. After D-Day, he had already smelted several furnaces of steel, proving that steel could be made from charcoal and local pig iron products. The disadvantage was that it was difficult to grasp the proportion of materials, so what kind of steel could be produced each time was entirely a matter of luck. Another thing was that the energy consumption of the metallurgical department was really large. Just during steelmaking, the two blowers would have to shut down all nearby electricity-using departments.

Based on the chemical analysis of the pig iron, the metallurgy group adopted a side-blown converter method for ironmaking. This method required the addition of a certain proportion of wrought iron, roughly 76% pig iron and 24% wrought iron. A very small amount of sand was also needed. The purpose of the sand was to create an acidic slag to absorb the phosphorus contained in the pig iron.

After discovering local refractory materials, the metallurgy group had already built a cupola furnace. This circular melting furnace was not large, but it was much more complex than a converter, because the converter required the molten iron from the cupola to reach 1380 degrees Celsius. This temperature was difficult to achieve with ordinary fuels. Before the invention of the regenerative chamber, the highest temperature that could be reached manually was 1250 degrees Celsius.

To reach this temperature, the cold blast had to be replaced with a hot blast. This is the so-called “regenerative chamber.” The concept of the hot blast was invented by the Englishman James Beaumont Neilson and was applied in the ironworks of Glasgow in 1829.

The technological level of the regenerative chamber adopted by the metallurgy group was roughly equivalent to that of a British steel plant in 1850. They used a cast-iron pipe-type hot blast stove. The cold blast passed from the branch pipe on the main blast pipe to each heating furnace, and then through an arched cast-iron pipe located above the fire into the pipe on the other side of the heat exchange chamber, and finally into the tuyere of the cupola furnace. The entire device was sealed in a thick arched heating furnace built with bricks and refractory materials to preserve and reflect as much heat as possible. After being directly heated, the temperature of the blast could rise to 300 degrees Celsius, enough to melt lead. But this temperature still did not satisfy the metallurgy group. Another measure adopted was waste gas heating. The waste gas from the top of the melting furnace was led out through ceramic pipes, entered the regenerative furnace from the upper part, and was then discharged from the waste gas outlet at the lower part.

A large amount of coal gas is produced in a melting furnace that uses coal or coke. For centuries, this gas was basically discharged from the top of the furnace. The roaring flames when the gas burned were very spectacular at night, but it was a serious waste of energy and polluted the environment. Therefore, in 1832, an ironworks in Baden, Germany, was the first to transport the coal gas through pipes to a regenerative furnace for heating. Various methods would eventually raise the temperature of the hot blast to over 500 degrees Celsius.

Without a regenerative furnace, it is also possible to make iron or steel, but the production efficiency is completely incomparable. According to British calculations, an early regenerative furnace that raised the blast temperature to over 300 degrees Celsius increased the iron output by 3 times for the same amount of fuel compared to a cold blast.

The high-temperature hot blast would damage the tuyere of the melting furnace and must be protected. The transmigrators’ technological level was already sufficient to overcome this problem. They easily copied the Scottish tuyere invented by Condie of the Scottish ironworks. This tuyere had a wrought iron coil embedded in a cast iron conical tube, with both ends extending from the bottom surface of the conical sleeve, one on each side. Water flowed in from one end of the protruding pipe and flowed to the narrow end of the tuyere. The water circulated in the coil and finally flowed out through the pipe protruding from the opposite side.

With this melting furnace, the metallurgy group was able to successfully produce steel in several small-scale steelmaking attempts. The next step is coking.

The transmigrators used charcoal in the early days, but coke was still the most ideal fuel. The significance of coal coking is not only to provide high-quality fuel for the steel industry, but the various by-products obtained during the coking process are also important raw materials in the chemical industry. For this reason, a complete set of coal coking equipment was brought in, which can not only produce coke, but also use its by-products to produce more than 20 important chemical products, including gasoline, diesel, asphalt, phenol, toluene, crude benzene, sulfuric acid, various solvent oils, lubricating oils, and paraffin. It can be said that once the coal coking complex is put into production, the transmigrators’ chemical industry level will have a qualitative leap.

However, just like all complete sets of equipment, the installation was very difficult. Despite having the manufacturer provide training in advance and preparing a large number of drawings, installation manuals, and special equipment, the progress was still slow in the hands of a group of amateur installers. Moreover, this system was a continuous operation type and could not be started and stopped frequently. A single charge required hundreds of tons of coal. The transmigrators’ entire coal reserve was only 20 tons. Therefore, the metallurgy group could only adopt a simple, indigenous method of coking.

There are many indigenous methods of coking. The simplest is the open-air piling method, where 2-4 tons of coal are piled into a semi-circular heap on the ground, with a bottom diameter of 3-4 meters. It is then covered with straw and ignited. It takes 4-5 days to become coke, with a coking rate of only 50%. This method was also used during the Great Leap Forward for steel production, causing extremely serious resource waste and environmental pollution. The transmigrators could ignore environmental issues, but coal tar is an important raw material for the chemical industry and cannot be wasted casually.

Luo Duo once again found an improved plan from the computer’s science and technology resource library, using a Kailuan round furnace for coke production. The Kailuan furnace has three different specifications, with the amount of charge per batch ranging from 55 tons to 260 tons. The 55-ton furnace has the best cost-performance ratio and also fits the transmigrators’ current situation of limited coal in the initial stage.

The building materials are also very simple. Except for a few parts that require iron sheets, the basic materials are bricks and refractory bricks. The entire coking process takes about 12 days, with a coking rate of 75%. This type of furnace can use the coal gas produced during coking to heat the coking furnace, and at the same time, it can recover a portion of the coal tar. This tar, after being cooled and recovered with water, is collected in pottery jars, ready to be used as a chemical raw material in the future.

Finally, the coke and pig iron were ready. Ji Wusheng gathered the steelworkers. These transmigrators, who had recently changed their profession, put on asbestos protective clothing and gloves, and wore special hats and color-changing goggles. He reiterated a few key points to the people at each operating position: first, the air volume must be adjusted evenly and not fluctuate; second, when pouring the molten iron into the furnace, it should not be higher than the tuyere, otherwise the tuyere will be blocked; finally, the amount of molten iron poured each time should not exceed one-sixth of the converter’s chamber.

The two blowers began to operate simultaneously. One blew air into the cupola furnace, gradually raising the temperature to over 1300 degrees Celsius. The pig iron ingots had completely melted. At this time, Ji Wusheng directed the workers to add 0.4% baking soda for desulfurization. At the same time, the converter was preheating. According to the requirements, the entire converter had to be preheated to 1000 degrees Celsius to reduce the temperature loss after the molten iron entered.

When the optical thermometer showed that the temperature of the molten iron in the cupola furnace had reached 1380 degrees, the molten iron was poured into the converter to begin blowing. At this time, the blast pressure of the blower was maintained at 0.07-0.12 atmospheres. The molten iron continued to heat up under the impetus of the high-temperature hot blast. Ji Wusheng stared intently at the flames in the furnace. One after another, iron sparks burst out. The flames were reddish-yellow, then yellowish-white to white, and finally completely bright white, which indicated that the furnace temperature was constantly rising.

The blowing lasted for about ten minutes. The density of the star-shaped carbon sparks continued to increase, and the bright white flames grew from short to long. At this time, the combustion of carbon reached its peak.

When Ji Wusheng saw the flames begin to shorten and the carbon sparks become sparse, he knew that the remaining carbon content in the molten iron was approaching that of steel. He raised and lowered the furnace-rocking lever once or twice to see if more carbon sparks would burst out. When he saw that the carbon sparks did not suddenly increase, he ordered the blast to be turned off.

Afterwards, the workers removed the furnace cover and the blast pipe, and began to remove the slag. Finally, they poured the steel. The molding sand used was 90% yellow sand, 5% clay, and 5% white clay. After casting, it became a steel ingot. As for whether this steel ingot was high-carbon, medium-carbon, or low-carbon, Ji Wusheng could not yet control it. After each furnace was produced, a test had to be done to determine what kind of steel it was.